In Germany, a debate that appears to be about one thing is often really about something quite different.

A controversy last year over what to do about fighting breeds of dog was, in part, about cracking down on the far right. A controversy this year over the birth rate was, at root, about how the country could reduce the need for mass immigration.

In the past few days, the chancellor, Gerhard Schröder, and the president, Johannes Rau, have become involved in what appears to be a public row over bio-technology. The debate has been bubbling away ever since Britain decided to allow embryonic tissue to be used for stem cell research.

There is probably no other apparently secular nation where tampering with life in any form is such a sensitive issue as it is in Germany. When the Netherlands legalised euthanasia earlier this year, the reaction was one of widespread revulsion, provoking memories of the Nazis' attempts to create a master race.

At the end of last week, President Rau expressed this repugnance most forcibly. In a speech that called for a strict limit to genetic research, he said: "Eugenics, euthanasia and selection - these are terms that, in Germany, are bound up with bad memories."

President Rau also voiced concern over the practice of pre-implantation diagnosis, which is permitted in some other European countries, and which allows embryos to be tested for hereditary diseases before implantation in the womb. He argued that such practices opened the door to the "biological selection" of children.

His remarks were clearly designed to cut the ground from under Mr Schröder who, just a few days earlier, had seemed to hint at a change in Germany's conservative laws on bio-technology. German law, dating from 1990, bans research that uses embryos. The president, however, insisted that it was "a good law and we have every reason to leave it as it is for now".

The chancellor hit back by saying that the discussion so far had not taken "enough account of the economic dimension" and that it was "also our moral responsibility to take care of our jobs and well-being". Britain has overtaken Germany in the bio-technology race, and Schröder wants Germany to catch up.

President Rau is coming at the issue from a markedly different philosophical standpoint - his viewpoint is as devoutly Christian as Mr Schröder's is patently secular. His deep religious convictions have earned him the nickname of "Brother Johannes". Mr Schröder, by contrast, had the words "so help me God" cut out of the oath he swore on assuming office three years ago.

The chancellor's worries, as he intimated in an interview with Der Spiegel news magazine this week, are still very much in the here and now. He urged his compatriots "not to forget the many people with serious illnesses who can hope for cures and relief from drugs produced by genetic technology".

So far, Mr Schröder's arguments have failed to cut much ice with opinion-formers. This week, the leading left-of-centre daily, Süddeutsche Zeitung, was, effectively, seeing eye to eye with perhaps the most conservative of the mainstream papers, Die Welt.

Süddeutsche Zeitung accused Mr Schröder of trying to curb discussion, adding that "foreshortening the debate in this way is dangerous and corresponds to the naïve faith in progress that [President] Rau warned against".

Die Welt said the head of state's speech had "come at the right time in the right place and given him the aura of a German Pope", no less.

If the editorialists are anything to go by, it seems that Germans are ready to forgo a competitive advantage for the sake of ethical rigour. President Rau appears to have been speaking for the majority when he said: "What is ethically indefensible cannot be permitted for economic reasons."